Ebook Ecosystems

Life Science by Helen N. George Genre Nonfiction Comprehension Skill Sequence Text Features · Captions · Call Outs · Text Boxes · Glossary Science Content Ecosystems Scott Foresman Science 4.3 ì<(sk$m)=bdigfe< +^-Ä-U-Ä-U Vocabulary carnivores community Ecosystems by Helen N. George decomposers ecosystem herbivores niche omnivores population Illustration: Title Page, 4 Bob Kayganich Photographs: Every effort has been made to secure permission and provide appropriate credit for photographic material. The publisher deeply regrets any omission and pledges to correct errors called to its attention in subsequent editions. Unless otherwise acknowledged, all photographs are the property of Scott Foresman, a division of Pearson Education. Photo locators denoted as follows: Top (T), Center (C), Bottom (B), Left (L), Right (R) Background (Bkgd) Opener: ©Breck P. 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For information regarding permissions, write to: Permissions Department, Scott Foresman, 1900 East Lake Avenue, Glenview, Illinois 60025. 3 4 5 6 7 8 9 10 V010 13 12 11 10 09 08 07 06 05 What are the parts of ecosystems? What a System Is A system has parts. These parts work together to do a job. A system can have living and nonliving parts. Every part of a system is important. The system will not work as well if any part is damaged or missing. A bicycle is a simple system. The frame, handlebars, and the rider all work together. Most ecosystems need inputs. Inputs are things coming into the system. They also need outputs. Outputs are things leaving the system. The activity of the rider is an input of a bicycle system. The dust from the tires is one output. 2 Ecosystems An ecosystem is all of the living and nonliving things in an environment. It also is how they interact. An ecosystem can be as large as a desert. It can be as small as a rotting cactus. The living things in an ecosystem are animals, plants, fungi, protists, and bacteria. The nonliving things in an ecosystem are air, water, soil, sunlight, climate, and landforms. The living and nonliving parts work together. 3 Kinds of Ecosystems The needs of an organism must be met in its environment. Some plants and animals will survive in the environment better than others will. Some will not survive at all. Soil and climate affect which plants and animals will do well in an area. Desert plants and animals have adaptations to help them live in a dry environment. The giant saguaro cactus can fill up with water. It can store this water until the next rainfall. Tundra A tundra is cold and dry. The ground under the surface is frozen all year long. Some grasses can grow. Trees cannot grow. Caribou and arctic foxes do well during the spring and summer. Forest Forests get more rain than grasslands do. Forests have many animals, trees, and wildflowers. Some forest animals are squirrels, raccoons, deer, and foxes. Tropical Rain Forest A rain forest is always wet. There are many species of plants and animals in the rain forest. Colorful birds live there. Beautiful flowers live there. Desert A desert is the driest ecosystem. Plants and animals adapt to live with little water. Some desert organisms are roadrunners, coyotes, shrubs, and cactuses. Grasslands Grasslands are covered with tall grasses. They have moderate rainfall. Bison, prairie chickens, and grasshoppers are found in North American grasslands. 4 5 Organisms and Their Environment A population is one species of organisms that live in a part of an ecosystem. Prairie dogs make up one animal population in a desert. Barrel cactuses make up a plant population in the desert. The size of a population depends on how much water, food, and space there is. Different populations can live together in the same area. They make up a community. All the organisms found in a desert ecosystem are a community. A habitat is where an organism lives within an ecosystem. The habitat of the Gambel’s quail is near shrubs in the Sonoran desert. It can hide from predators there. Everything an organism needs to survive is found in its habitat. 6 Special Roles Every organism has a job to do in its habitat. This is its niche. A niche includes the food the organism eats, how it gets its food, and which other species use the organism for food. Every population in a habitat has a different niche. Hummingbirds and roadrunners share a desert habitat. They have different niches. The Lucifer hummingbird eats small insects, spiders, and nectar from plants. It hides from its enemies, such as the roadrunner, by sitting on tall plants. The roadrunner’s niche is to hunt scorpions, lizards, and snakes. It runs away from enemies, such as the coyote. 7 ... - tailieumienphi.vn